This application claims the benefit of Japanese Application No. 2000-017401 filed in Japan on Jan. 26, 2000, the contents of which are incorporated herein by this reference.
1. Field of the Invention
The present invention relates to a camera with a data exposure function and more particularly to a camera with a data exposure function capable of exposing data such as date data when a film frame is wound up.
2. Related Art Statement
Conventionally, a camera with a data exposure function has been proposed in which dot-matrix like data is exposed to a film face by lighting plural light emission devices a plurality of times during feeding of a film. Such a camera with a data exposure function is an example disclosed in, for example, Japanese Patent Application Laid-Open No. HEI7-319048.
In the camera with a data exposure function disclosed in the same publication, the number of pulse signals generated with a rotation of a film feeding motor is stored corresponding to a predetermined film feeding amount. Next, a time necessary for counting the number of pulse signals corresponding to the rotation of a film feeding motor is measured and a film feeding time corresponding to a predetermined film feeding amount is calculated. As a result, a lighting interval of the light emission device is controlled by the calculated time.
However, in the camera disclosed in the aforementioned Japanese Patent Application Laid-Open No. HEI7-319048, because the film feeding time corresponding to the predetermined film feeding amount is calculated and the lighting interval of the light emission devices is controlled in accordance with this calculated time, if the film is jammed during data exposure, an error in lighting interval may be generated. At this time, the shape and dimension of data exposed to the film become inaccurate.
An object of the present invention is to provide a camera with a data exposure function capable of exposing data to the film surface with small error in shape and dimension thereof.
To achieve the above object, according to an aspect of the present invention, there is provided a camera with a data exposure function for exposing data relating to characters, numerals or symbols by lighting a plurality of light emission devices interlockingly with a film feeding operation thereof, comprising: a film feeding motor; a motor pulse signal output portion for outputting a motor pulse signal with rotation of the film feeding motor; a perforation detecting portion for detecting a perforation provided in the film so as to output a perforation signal; a counting portion for counting the number of the motor pulse signals generated since a perforation is detected by the perforation detecting portion until another perforation is detected; a determining portion for determining a lighting interval pulse for controlling at least a lighting interval of the light emission device based on a value counted by the counting portion; a motor pulse period measuring portion for measuring a period of the motor pulse signal; a correction time calculating portion for calculating a correction time corresponding to a decimal portion of the lighting interval pulse based on the decimal portion of the lighting interval pulse and a motor pulse period measured by the motor pulse period measuring portion; and a control portion for controlling a lighting interval of the light emission device using an integer portion of the lighting interval pulse determined by the determining portion and the correction time calculated by the correction time calculating portion.
According to another aspect of the present invention, there is provided a camera with a data exposure function comprising: a data exposure portion including plural light emission devices disposed in a direction perpendicular to a film feeding direction; a film feeding portion for winding a film after exposure by a frame by controlling a film feeding motor; a motor pulse signal outputting portion for outputting a motor pulse signal corresponding to a rotation amount accompanied by the rotation of the film feeding motor; a perforation detecting means for detecting a perforation provided in the film to output a perforation signal; a counting portion for counting the number of the motor pulse signals in a period in which particular two perforations are detected by the perforation detecting portion; a determining portion for determining a lighting interval pulse for controlling a lighting interval of the light emission device based on a value counted by the counting portion; a correction time calculating portion for calculating a correction time corresponding to a decimal portion of the lighting interval pulse determined by the determining portion with reference to a period of the motor pulse signal; and a control portion for exposing data relating to characters, numerals or symbols to the film by controlling a lighting interval of the light emission devices in the data exposure means, based on an integer portion of the lighting interval pulse determined by the determining portion and a correction time calculated by the correction time calculating portion.
According to still another aspect of the present invention, there is provided a data exposure method of a camera with a data exposure function for exposing data relating to characters, numerals or symbols by lighting a plurality of light emission devices interlockingly with a film feeding operation thereof, comprising: a step of outputting a motor pulse signal with a rotation of a film feeding motor; a step of detecting a perforation provided in the film; a step of counting the number of the motor pulse signals in an interval since a predetermined perforation is detected until a subsequent perforation is detected; a step of measuring the period of the motor pulse signal; a step of determining a lighting interval pulse for controlling a lighting interval of the light emission device based on the counted value; a step of calculating a correction time corresponding to a decimal portion of the lighting interval pulse by calculating the decimal portion of the lighting interval pulse and the period of the motor pulse signal; and a step of controlling the lighting interval of the light emission devices using an integer portion of the determined lighting interval pulse and the correction time.
These objects and advantages of the present invention will become further apparent from the following detailed explanation.